This invention relates to the creation of electrochromic structures through which energy, including light, can be transmitted under controlled conditions, and more particularly, to electrochromic structures for the controlled energy transmission.
A wide variety of chromogenic structures are available for controlling the through-passage of energy. Such devices operate "chromatically" by producing a change in coloration in accordance with an applied stimulus or excitation.
Thus, a thermochromic device produces a color change in response to temperature. The resultant coloration of, for example, a sheet of material, depends upon the temperature to which the sheet is subjected. There is, however, the objection that a user has only limited control over the coloration since it is temperature dependent.
Another chromogenic device is "photochromic" in that its coloration depends upon the intensity of light that falls upon the device. When glass or other transparent materials are doped with silver halide, a light-induced reaction produces increased darkening with increased intensity of light. Here again, the degree of coloration is dependent upon external effects.
Still another chromogenic device depends upon the extent to which an electrical stimulus is applied and thus is termed "electrochromic". In such devices the nature and extent of coloration depends upon an electrical effect.
Unfortunately, it has been difficult to produce economically electrochromic devices with useful properties, particularly large-scale devices. Consequently, it has been difficult to produce panels with surfaces of the kind needed for architectural windows, skylights and other transparent substrate based products. It also has been difficult to produce economically electrochromic sun glasses, goggles and automotive products.
Accordingly, it is an object of the invention to facilitate the manufacture and use of chromogenic structures. A related object is to facilitate large scale chromogenic applications in which appreciable surface areas are required.
Still another object of the invention is to adapt chromogenic devices to light transmissive structures such as skylights and other arrangements that are intended to provide control over natural illumination over relatively large areas.
A further object of the invention is to facilitate the manufacture and use of electrochromic structures, particularly for relatively large scale applications.